Knife bolster



FIG. 1 is a left side perspective view of the knife bolster, showing my new design.

FIG. 2. is a left-side view thereof, the right-side being a mirror image.

FIG. 3 is a top view thereof.

FIG. 4 is a bottom view thereof.

FIG. 5. is a rear view thereof; and,

FIG. 6 is a front view thereof.

The broken lines shown in the drawings illustrate the enviroment of the claimed design and form no part thereof. 

CLAIM The ornamental design for a knife bolster, as shown and described. 